He didn't say which mill. This afternoon, however, Georgia-Pacfiic announced it would shut down its Duluth board plant because it couldn't get the proper permitting in the shutdown.
The Duluth News-Tribune reports:

Georgia-Pacific's board plant in Duluth is shutting down today because the company could not renew its water-use permit during the Minnesota state government shutdown.

The Duluth plant at 1220 W. Railroad St. uses water from Lake Superior to cool its processing equipment and then returns it.

Nearly 150 people are employed at the plant that makes Superwood, a thin hardboard used extensively in the auto industry.

"We've had to temporarily shut down operations," said Melodie Ruse, a Georgia Pacific spokeswoman in Atlanta.

Ruse said the company continues to seek a solution to the problem and the company expects to file a petition Thursday with the state seeking an exemption during the government shutdown. Until the state acts, however, all employees will be out of work, Ruse said.